According to conventional high pressure liquid chromatography (HPLC), packing materials with silica gel as support have been generally employed. The packing materials in which one or more organic functional groups are joined on the surface of the silica gel have various uses about many fields of chemistry. Such packing materials are in low absorption and have high resolving power, but only they can be applied in the narrow pH range, generally between pH 2 and 8.
In the process of producing the packing materials, silica hydroxyl groups are not reacted perfectly with the functional groups of an additive. As the result, some residual silica hydroxyl groups remain on the surface of the silica gel. In the case of analysis of biological sample such as proteins, a certain kind of solute is strongly adsorbed and retained in the packing material, thus the separating ability of the material is insufficient from the chromatographic standpoint.
For this reason, Japanese Patent Open Publication No. 5941/80 has described that an organic silane compound with epoxy groups as end groups is bound to the surface of silica gel, which is further copolymerized with an organic compound having other epoxy groups. Japanese Patent Open Publication No. 93043/81 has shown that an organic silane compound whose end groups are epoxy groups is bound to the surface of inorganic particles e.g. silica gel, and then mono-, di- or trisaccharide is bound chemically to the epoxy groups on the silane moieties, thereby the influence of residual silica hydroxyl groups is eliminated more and more. According to Japanese Patent Open Publication No. 5941/80 or No. 93043/81, the applicable range of the pH is not very wide because dissolution of the packing material begins to occur from the pH of about 10. It is assumed that the silica hydroxyl groups unreacted still remain from the result of polymerization degree of the organic compound added and other reasons.
Recently, since the applicable range of to be analyzed substances has became wider and wider, an organic support made from one or more synthetic resins have also been proposed, as described in Japanese Patent Open Publications No.76989/77, No.106357/80 and No.60261/82. The organic support is excellent in resistance against alkali and acid, but it is weak in mechanical strength. As the organic support also has a hard problem in swell, contraction and the like by addition of solvent and then remarkably lowers the column efficiency of HPLC, it is impossible to apply the support to new analytical fields.